Aerospaceplane (1958-1963)

[Dynoman]

An air launched Aerospaceplane from an XB-70

 

[Archibald]

Wasn't that a Republic concept ? (well, d'oh, of course it is, as shown on this thread first two pages).

 

[flateric]

An air launched Aerospaceplane from an XB-70

https://www.secretprojects.co.uk/threads/republic-1965-mach-12-hypersonic-recon-project-and-demonstrator.38549/post-512588

 

[Archibald]

Ok, so the Internet Archive has some Aviation Week magazines for free, and I've found a little Aerospaceplane gem from July 1963. I've split it, OCR and cleaned up.
Most important thing here: a detailed breakdown of Air Force Special Requirement SR.651 multiple propulsion developments. From SR.651B to SR.651J, including HIRES as SR.651H (hypersonic in-flight refueling, don't try this at home LMAO).

The major effort associated with Aerospaceplane has gone into studies, applied research and development of propulsion systems. A whole family of systems using liquid hydrogen as a base and ranging from air-breathing to pure rockets using liquid oxygen, have been explored.
The breakdown of studies under SR.651 is:
SR.651B—Air collection enrichment subsystems. This includes air compressors; liquid air separators, heat exchangers and tankage. Marquardt Corp. And Linde Air Products Corp. did work in this area. (SR 651A was a study of all the propulsion technologies and was supplanted by the more detailed studies listed here.)
SR.651C—Mach 8 ramjet. This effort is aimed at providing a subsonic air flow ramjet which will go beyond the present Mach 3-4 ramjets to Mach 8, the speed at which the second stage would be launched. Marquardt is doing this.
SR.651D — Liquid air cycle engine (LACF). Marquardt is following this.
SR.651E-Supersonic combustion ramjet (SCRAM). Marquardt. General Electric Co. at Evendale. Ohio, and General Applied Sciences Laboratory at Westbury, N. Y., arc doing applied research in this area. SCRAM is in such an early stage that it probably would be applied to the second-generation Aerospaceplane.
SR.651F—Turbo-accelerator (advanced turbo-ramjet). No company has been selected for this work.
SR.651G—Advanced structures and materials. Lockheed, North American, Solar, Armour Research Laboratory, General Dynamics/Astronautics and Texas Instruments, Inc., are working in this area.
Two other studies have been recommended and are awaiting approval.
They are:
SR.651H—Hypersonic inflight refueling subsystems (HIRES).
SR.651J—Aerospaceplane aerodynamics.

My pet peeve, albeit suborbital rather than hypersonic. Nice to hear about it from a contemporary source (1963) rather than the classic NASA histories by Jenkins, Heppenheimer and co.

 

[abheiden]

An air launched Aerospaceplane from an XB-70

That must be one of the bravest daredevil pilots i ever seen in that launch under that XB-70

 

[Archibald]

The way the XB-70 carries it : either it ruins the flight characteristics through massive asymmetry; or the huge asymmetrical drag has the Valkyrie unable to break the sound barrier, de facto turning it into a very expensive NB-52. What's more, ramjet / scramjet vehicles tends to be draggy, too, if only because the engine doesn't work properly below mach 3.
So the whole thing is a drag nightmare.
XB-70 may have dropped large aerospace vehicles at mach 3, but only from inside that streamlined big belly fairing: with a "bomb" bay carved inside. But from the back or from a wing pylon ? no and NO. Bad idea. Definitively.

 

[Dynoman]

Original Aerospaceplane designed by Propulsion Lab Chief Scientist Weldon Worth (AFRL/RQ).

 

[Orionblamblam]

Original Aerospaceplane designed by Propulsion Lab Chief Scientist Weldon Worth (AFRL/RQ).

Is there more info/documentation on that?

it seems unlikely to be an Aerospaceplane... there's no LOX tankage. LH2 and JP-6, but no LOX and no evidence of rocket engines. It could go high and fast, but not attain orbit.

 

[Dynoman]

Is there more info/documentation on that?

No, just the picture through the AFRL, identified as the original Aerospaceplane by the propulsion lab Chief Worth.

 

[Archibald]

Maybe it was just a scramjet demonstrator ? Weldon Worth was influenced by Republic's Antonio Ferri, and this concept looks like Republic Aerospaceplane (from memory).

 

[leovinus2001]

Late to the party but I was wondering whether anyone tried already to get their hands on the original contractor reports like these four? From Republic and Douglas? In addition, any ASTIA AD numbers for these? This is from the "Hypersonic revolution", p854
- Republic Aviation Corp. Reports related to single-stage-to-orbit orbit studies, 1961-62. RAC 430, 730, and 1306.
- Republic Aviation Corp., 2-Stage Aerospaceplane Study, RAC 1370-20-I, January 28, 1964.
- Douglas Aircraft Co., 2-Stage Aerospaceplane Study. DAC 47551, 1964.
- Feasibility studies evaluation report SR-89774 (Phase II) Recoverable Booster Systems AD-343 143L

 

[Archibald]

Nice to see you here, Leovinus !

 

[leovinus2001]

Late to the party but I was wondering whether anyone tried already to get their hands on the original contractor reports like these four? From Republic and Douglas? In addition, any ASTIA AD numbers for these? This is from the "Hypersonic revolution", p854
- Republic Aviation Corp. Reports related to single-stage-to-orbit orbit studies, 1961-62. RAC 430, 730, and 1306.
- Republic Aviation Corp., 2-Stage Aerospaceplane Study, RAC 1370-20-I, January 28, 1964.
- Douglas Aircraft Co., 2-Stage Aerospaceplane Study. DAC 47551, 1964.
- Feasibility studies evaluation report SR-89774 (Phase II) Recoverable Booster Systems AD-343 143L

A bit more sleuthing via

Technical Abstract Bulletin (TAB) 15 August 1964

https://babel.hathitrust.org/cgi/pt?id=coo.31924057185880&seq=153&q1=aerospaceplane

gives me the below.

Couple of notes
a) Above I asked about
- Republic Aviation Corp., 2-Stage Aerospaceplane Study, RAC 1370-20-I, January 28, 1964.
while below I only found RAC 1370-21 reports. Note the 21 vs 20. Therefore, it stand to reason that the 'Republic Aviation Corp., 2-Stage Aerospaceplane Study" AD number are still to be found.
b) For
- Douglas Aircraft Co., 2-Stage Aerospaceplane Study. DAC 47551, 1964.
The report numbers 47551 matches and are consecutive.
c) Not sure whether there were other contractors but maybe search for earlier AF(33)-657 10988 or later AF(33)-657 10992 will work
d) Anyone has any copies ?

1) Douglas Aircraft Co InC., Long Beach. Calif.,
Contract AF33 657 10990, Proj. 7990. Task 799001
(or written as AF(33)-657 10990 )
18 Mar 1963 - 30 Apr 1964

- AD-351 463L, AEROSPACEPLANE PLANNING STUDY., VOLUME I STUDY, SUMMARY (U)., 75 pages, Rept. no. 47551
- AD-351 468L, AEROSPACEPLANE PLANNING STUDY., VOLUME II Development (U), 358 pages, Rept. no. 47552
- AD-351 464L, AEROSPACEPLANE PLANNING STUDY., VOLUME III Costing (U), 64 pages, Rept. no. 47553
- AD-351 540L, AEROSPACEPLANE PLANNING STUDY., VOLUME IV Vehicle Performance (U), 253 pages, Rept. no. 47554
- AD-351 541L, AEROSPACEPLANE PLANNING STUDY., VOLUME V Propulsion and Refueling (U), 507 pages, Rept. no. 47555
- AD-351 542L, AEROSPACEPLANE PLANNING STUDY., VOLUME VI Structure and aero heating (U), 685 pages, Rept. no. 47556
- AD-351 543L, AEROSPACEPLANE PLANNING STUDY., VOLUME VII Guidance, Control and Subsystems (U), 335 pages, Rept. no. 47557

2) Republic Aviation, Farmingdale, NY
Contract AF33 657 10827, 28 jan 1964
- AD 351 581, 314 pages, Final summary report, Volume I (U) Rept. no. 1370 21 1
- AD 351 582, 174 pages, Evaluation of P&W Turboramjet Engines in Republic Aerospaceplane, Volume II (U), Rept. no. 1370 21 2
- AD 351 583, 154 pages, Evaluation of G.E. TURBORAMJET ENGINES IN REPUBLIC AEROSPACEPLANE, VOLUME III (U), Rept. no. 1370 21 3
- AD 351 584, 61 pages, Evaluation of MARGUARDT SUPERLACE ENGINES IN REPUBLIC AEROSPACEPLANE, VOLUME IV (U), Rept. no. 1370 21 4

3) General Dynamics/Astronautics (GD/A), San Diego , CA
Contract AF33 657 10991, 30 Apr 1964
- AD-351 554L, DEVELOPMENT PLANNING STUDY 799001, VOLUME I ACES VEHICLE SYSTEM SUMMARY Summary (U), 148 pages, Rept. no. DCB64 046, Vol.1
- AD-351 555L, DEVELOPMENT PLANNING STUDY 799001, VOLUME II, VEHICLE CONFIGURATION STUDIES (U), 286 pages, Rept. no. DCB64 046, Vol.2
- AD-351 556L, DEVELOPMENT PLANNING STUDY 799001, VOLUME III AERODYNAMIC PARAMETRIC & ANALYTICAL STUDIES (U), 198 pages, Rept. no. DCB64 046, Vol.3
- AD-351 557L, DEVELOPMENT PLANNING STUDY 799001, VOLUME IV, PROPULSION PARAMETRIC AND ANALYTIVCAL STUDIES (U), 198 pages, Rept. no. DCB64 046, Vol.4
- AD-351 558L, DEVELOPMENT PLANNING STUDY 799001, VOLUME V, STRUCTURE PARAMETRIC AND ANALYTIVCAL STUDIES (U), 233 pages, Rept. no. DCB64 046, Vol.5
- AD-351 559L, DEVELOPMENT PLANNING STUDY 799001, VOLUME VI, VEHICLE SUBSYSTEMS AND AEROSPACE GROUND EQUIPMENT (U), 182 pages, Rept. no. DCB64 046, Vol.6

4) North American Aviation (NAA) , Los Angeles, CA
Contract AF33 657 10989, Proj. 7990. Task 799001, 30 Apr 1964
- AD 351 567L, AEROSPACEPLANE, PLANNING STUDY, POBATO/CR CONCEPT, VOLUME SUMMARY REPORT, Rept. no. 64. 300, vol 1
- AD 351 549L, AEROSPACEPLANE, PLANNING STUDY, POBATO/CR CONCEPT, VOLUME II, PARAMETRIC STUDY, 465 pages, Rept. no. 64. 300, vol 2
- AD 351 550L, AEROSPACEPLANE, PLANNING STUDY, POBATO/CR CONCEPT, VOLUME III, SYSTEM DESCRIPTION (U), 592 pages, Rept. no. 64. 300, vol 3
- AD 351 551L, AEROSPACEPLANE, PLANNING STUDY, POBATO/CR CONCEPT, VOLUME IV, PROGRAM PLAN (U), 257 pages, Rept. no. 64. 300, vol 4
- AD 351 552L, AEROSPACEPLANE, PLANNING STUDY, POBATO/CR CONCEPT, VOLUME V, COST EVALUATION, 113 pages, Rept. no. 64. 300, vol 5
- AD 351 553L, AEROSPACEPLANE, PLANNING STUDY, POBATO/CR CONCEPT, VOLUME VI, ALTERNATE PLAN, Rept. no. 64. 300, vol 6
- AD 351 544L, AEROSPACEPLANE, PLANNING STUDY, POBATO/CR CONCEPT, VOLUME VII, PART I, SUPPORTING FIGURES AND DATA VEHICLE CONFIGURATION (U), 549 pages, Rept. no. 64. 300, vol 7, pt 1
- AD 351 545L, AEROSPACEPLANE, PLANNING STUDY, POBATO/CR CONCEPT, VOLUME VII, PART II, SUPPORTING FIGURES AND DATA PROPULSION (U) , 1653 pages, Rept. no. 64. 300, vol 7, pt 2
- AD 351 546L, AEROSPACEPLANE, PLANNING STUDY, POBATO/CR CONCEPT, VOLUME VII, PART III, SUPPORTING FIGURES AND DATA STRUCTURES, 635 pages, Rept. no. 64. 300, vol 7, pt 3
- AD 351 547L, AEROSPACEPLANE, PLANNING STUDY, POBATO/CR CONCEPT, VOLUME VII, PART IV, SUPPORTING FIGURES AND DATA SUBSUBSYSTEMS, 977 pages, Rept. no. 64. 300, vol 7, pt 4
- AD 351 548L, AEROSPACEPLANE, PLANNING STUDY, POBATO/CR CONCEPT, VOLUME VII, PART V, SUPPORTING FIGURES AND DATA WEIGHT ANALYSIS, 126 pages, Rept. no. 64. 300, vol 7, pt 5

 

[Archibald]

POBATO : Propellants On Board At Take Off. In opposition to HIRES : Hypersonic Inflight REfueling System (all in the name, they wanted to try it with with X-15s but mercifully backed down).

 

[leovinus2001]

A bit more sleuthing via

A bit more, but information is missing to assign these reports to companies. I suspect the t"set1" is from Republic Aviation (because of the Superlace and P&W studies). Set2 no idea. Set3 Maybe from the USAF program committee. What do you think?

Set1:
- AD-345 591L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. SECOND STAGE PROPULSION OPTIMIZATION USING ENGINE DATA FROM PRATT AND WHITNEY AIRCRAFT DIVISION OF UNITED AIRCRAFT CORPORATION
- AD-345 592L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. STAGING
- AD-345 593L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. TRAJECTORY VARIATIONS
- AD-345 594L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. EVALUATION OF THE USE OF A SPLIT INLET FOR COLLECT ENGINE MODE
- AD-345 595L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. EVALUATION OF PERIODIC HEAT EXCHANGE FOR AN AIR COLLECTION AND ENRICHMENT SYSTEM
- AD-345 596L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. EVALUATION OF THE USE OF CHEMICAL SEPARATION SYSTEM FOR AIR ENRICHMENT
- AD-345 597L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. ANALYSIS OF TAKE-OFF AND LANDIN FUEL REQUIREMENTS, DE-ORBIT REQUIREMENTS, AND LANDING ENGINE WEIGHT REQUIREMENTS
- AD-345 598L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. EVALUATION OF THE USE OF CARRIED LOX FOR TRANSONIC AND HIGHSPEED ROCKET OPERATION
- AD-345 599L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. DEFINITION OF TWO STAGE MODEL VEHICLE
- AD-345 600L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. SECOND STAGE PROPULSION OPTIMIZATION
- AD-345 601L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. SUMMARY OF PROPULSION EVALUATIONS AND RELATED STUDIES
- AD-345 602L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. THRUST AUGMENTATION WITH FIRST STAGE ROCKETS
- AD-345 603L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. EVALUATION OF TURBO RAMJETS ENGINES
- AD-345 604L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. EVALUATION OF PRATT AND WHITNEY AIRCRAFT TURBO RAMJET ENGINE
- AD-345 605L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. SECOND STAGE PROPULSION OPTIMIZATION USING ENGINE FATA FROM ROCKETDYNE
- AD-345 606L, AEROSPACEPLANE PROPULSION SYSTEM/ VEHICLE INTEGRATION STUDY. EVALUATION OF THE SUPERLACE PROPULSION SYSTEM

Set2:
- AD-351 039 AEROSPACEPLANE PROPULSION INTEGRATION STUDY, VOLUME 1
- AD-351 040 AEROSPACEPLANE PROPULSION INTEGRATION STUDY, VOLUME 3
- AD-351 041 AEROSPACEPLANE PROPULSION INTEGRATION STUDY, VOLUME 2

Set3:
- AD 360-889L, AERONAUTICAL SYSTEMS DIV WRIGHT-PATTERSON AF OH AEROSPACEPLANE, AN ADVANCED SYSTEN PLANNING STUDY (U) Technical documentary rept., Rept. No. ASD-TDR-53-690, Sept 1963.
- AD 360-890L, AERONAUTICAL SYSTEMS DIV WRIGHT-PATTERSON AF OH AEROSPACEPLANE, AN ADVANCED SYSTEN PLANNING STUDY (U) Technical documentary rept., Rept. No. ASD-TDR-53-690, Sept 1963.

EDIT: Typo

 

[Archibald]

From that document (too large too be attached) Dated September 1964, discussing a sensor for a refueling boom... at hypersonic velocities. Probably for the HIRES concept I mentionned a few times.



Make no mistake: hypersonic refueling would have been pilots suicide. Now, going suborbital instead...

 

[Archibald]

Excerpt from Air Force Magazine, May 1962 : a little gem I found through Google books.

 

[Archibald]

Another excerpt, same magazine but January 1961 edition; same author (Butz).

Pdf part-1 : page 49 to 53 according to the summary. Unfortunately the last two pages (52 & 53) are mostly missing - bad scan. If anybody knows how to find Air Force magazine, please let me know. It is extremely interesting stuff.

More excerpts to come from the same, massive document (904 pages of Air Force magasine covering the year 1961).
February 1961 (part-2)
March 1961 (part-3)

 

[Archibald]

And now - links toward the two massive documents. Can be read and downloaded entirely and for free. Note that I only browsed them looking for "Aerospace-plane". There is probably tons of interesting stuff inside besides aerospace-plane.

Of course I downloaded them on my HD (just in case Google goes enshittifying or deleting Google books)

1961 - https://www.google.fr/books/edition/Air_Corps_News_Letter/90EPAAAAIAAJ?hl=fr&gbpv=0

1962 - https://www.google.fr/books/edition/Air_Corps_News_Letter/S0MPAAAAIAAJ?hl=fr&gbpv=0

 

[Dew]

Another excerpt, same magazine but January 1961 edition; same author (Butz).

Pdf part-1 : page 49 to 53 according to the summary. Unfortunately the last two pages (52 & 53) are mostly missing - bad scan. If anybody knows how to find Air Force magazine, please let me know. It is extremely interesting stuff.

More excerpts to come from the same, massive document (904 pages of Air Force magasine covering the year 1961).
February 1961 (part-2)
March 1961 (part-3)

https://www.airandspaceforces.com/PDF/MagazineArchive/Documents/1961/February%201961/0261propulsion.pdf

..and complete edition:

https://www.airandspaceforces.com/app/uploads/1961/02/0261_February1961_LR.pdf

 

[moin1900]

Thanks! Interesting!

Especially Northrop's PROFAC (Propulsive Fluid Accumulator) manned magnetogasdynamic ramjet powered refueling station.

Sources:
AIR FORCE MAGAZINE, MARCH 1961, Page:52
- Air liquefaction and storage vehicle
(satellite tanker)

Western Aviation, Missile and Space Industries
March 1960
Volume 40, Number 3
Page: 16 & 24
"Magnetogasdynamics and Space Propulsion" by Sterge T. Demetriades
NORAIR DIVISION / NORTHROP CORPORATION
- Artist's conception "SPACE FUELING STATION"

US Spacecraft Projects #1
- PROFAC: flying gas station

https://www.secretprojects.co.uk/threads/us-spacecraft-projects-released.23305/

 

[Archibald]

Thank you so much @Dew ! How do you get the full Pdfs ?

Yes PROFAC is fascinating. It really was considered a part of Aerospaceplane as much as LACE and ACES - since all three had a similar objective : feeding rockets with atmospheric oxygen. As a complement of scramjet.

 

[moin1900]

AEROSPACEPLANE TEST VEHICLE
CONVAIR B-58 LACE TESTBED

https://www.secretprojects.co.uk/threads/b-58-lace-testbed.2538/

 

[Dew]

How do you get the full Pdfs ?

Here, for example: https://www.airandspaceforces.com/issue/year/1961/

 

[Archibald]

Here, for example: https://www.airandspaceforces.com/issue/year/1961/

Ah ok now I understand : it was my ad blocker that masked the pdfs.

I've just downloaded like a crazy caffeinated squirrel : from Sputnik to 1965. Feeling like a kid forgotten in a chocolate shop on Christmas day.

 

[Archibald]

A bit more sleuthing via

Technical Abstract Bulletin (TAB) 15 August 1964

https://babel.hathitrust.org/cgi/pt?id=coo.31924057185880&seq=153&q1=aerospaceplane

gives me the below.

Couple of notes
a) Above I asked about
- Republic Aviation Corp., 2-Stage Aerospaceplane Study, RAC 1370-20-I, January 28, 1964.
while below I only found RAC 1370-21 reports. Note the 21 vs 20. Therefore, it stand to reason that the 'Republic Aviation Corp., 2-Stage Aerospaceplane Study" AD number are still to be found.
b) For
- Douglas Aircraft Co., 2-Stage Aerospaceplane Study. DAC 47551, 1964.
The report numbers 47551 matches and are consecutive.
c) Not sure whether there were other contractors but maybe search for earlier AF(33)-657 10988 or later AF(33)-657 10992 will work
d) Anyone has any copies ?

1) Douglas Aircraft Co InC., Long Beach. Calif.,
Contract AF33 657 10990, Proj. 7990. Task 799001
(or written as AF(33)-657 10990 )
18 Mar 1963 - 30 Apr 1964

- AD-351 463L, AEROSPACEPLANE PLANNING STUDY., VOLUME I STUDY, SUMMARY (U)., 75 pages, Rept. no. 47551
- AD-351 468L, AEROSPACEPLANE PLANNING STUDY., VOLUME II Development (U), 358 pages, Rept. no. 47552
- AD-351 464L, AEROSPACEPLANE PLANNING STUDY., VOLUME III Costing (U), 64 pages, Rept. no. 47553
- AD-351 540L, AEROSPACEPLANE PLANNING STUDY., VOLUME IV Vehicle Performance (U), 253 pages, Rept. no. 47554
- AD-351 541L, AEROSPACEPLANE PLANNING STUDY., VOLUME V Propulsion and Refueling (U), 507 pages, Rept. no. 47555
- AD-351 542L, AEROSPACEPLANE PLANNING STUDY., VOLUME VI Structure and aero heating (U), 685 pages, Rept. no. 47556
- AD-351 543L, AEROSPACEPLANE PLANNING STUDY., VOLUME VII Guidance, Control and Subsystems (U), 335 pages, Rept. no. 47557

Late to the party but I was wondering whether anyone tried already to get their hands on the original contractor reports like these four? From Republic and Douglas? In addition, any ASTIA AD numbers for these? This is from the "Hypersonic revolution", p854
- Republic Aviation Corp. Reports related to single-stage-to-orbit orbit studies, 1961-62. RAC 430, 730, and 1306.
- Republic Aviation Corp., 2-Stage Aerospaceplane Study, RAC 1370-20-I, January 28, 1964.
- Douglas Aircraft Co., 2-Stage Aerospaceplane Study. DAC 47551, 1964.
- Feasibility studies evaluation report SR-89774 (Phase II) Recoverable Booster Systems AD-343 143L

The Douglas study would be highly interesting. Indeed Hallion says

The other companies studied various 2-stage versions of their earlier concepts, and a 2-stage refuelling concept was evolved by Douglas

And this is probably where HIRES is hidding : Hypersonic Inflight REfueling System.

 

[Archibald]

From Tom Heppenheimer Facing the heat barrier: A history of hypersonics

LACE: Liquid Air Cycle Engine

ACES : Air Collection and Enrichment System



AIAA paper 92-3499 attached.

 

[Archibald]

The AIAA document in turn lists a lot of Aerospaceplane tech papers.